There’s a lot we know about eggs: they are great for breakfast and you can cook them in different ways. One topic of debate, however, is why brown chicken eggs usually cost more than white ones. According to Shaman Hickman, the director of Community Outreach and Education for Hickman's Family Farms, genetics (基因学) not nutrition determines the eggshell colour and thus the egg’s price.
The chicken breed (品种) and their genetics decide whether or not hens have pigment (色素) genes, which coat the egg and result in a coloured shell during the egg-laying process. Although all eggs start out white in colour, shell colour can range from white to brown and even blue in some rare breeds, Hickman adds. Breeds such as the Leghorn chicken lay white eggs, while the Orpington lays brown eggs and the Ameraucana produces blue eggs.
Hickman notes that the Leghorn breed is the most efficient egg-laying hen, making it a popular choice for farmers. Hens that produce coloured eggshells, however, tend to be larger and require more feed and energy to create that painted layer. Since those breeds cost more to feed, their eggs are more expensive.
Although eggs sometimes look different and are priced differently, it’s impossible to know their nutritional make-up from the shell colour alone, according to Malkani, media spokesperson for the Academy of Nutrition and Dietetics. “Choosing between brown and white eggs is a matter of personal preference,” she says. “But it's important for people to know that the colour of the eggshell has nothing to do with the egg’s nutrient content or shell thickness.”
What does affect the nutrient content is the specific diet the hen is on, according to Malkani. For example, hens fed with a diet with omega-3s and vitamin D produce eggs that are higher in those specific nutrients. No matter what your preference is, don’t judge an egg by its shell colour.
【小题1】Which of the following is one of the arguments about eggs in Paragraph One?| A．Why Brown eggs are much cheaper. | B．How eggs can be cooked healthily. |
| C．Why coloured eggs are more expensive. | D．Whether brown eggs are great for breakfast. |
| A．The size of the hen. | B．The hen’s breed. |
| C．The colour of the eggs inside. | D．The environment of the laying process. |
| A．They are productive. | B．Their eggs are larger. |
| C．They lay brown eggs. | D．Their eggs sell better. |
| A．It takes efforts to test eggs’ nutrition. |
| B．It’s meaningless to study an egg’s colour. |
| C．Personal preference matters a lot in choice-making. |
| D．An egg's nutrition is closely related to the hen’s feed. |
